This invention relates to land and amphibious vehicles generally and in particular to amphibious earth moving equipment.
One type of amphibious vehicle has one or more pontoons around each of which an endless track is guided, the track being driven by a prime mover on the vehicle. The application of this technology to earth moving equipment enables one to produce excavators and the like suitable for use in marshy areas. The buoyancy of the pontoons is selected to be sufficient to prevent the vehicle from sinking and furthermore enables the tracks to drive the vehicle even in soft mud and mire. Various excavators and dredges of this type are well known.
Because of the limited demand for amphibious earth working vehicles, it is not commercially feasible to mass produce excavators specifically designed for marshy environments. Therefore, there is a demand for means to convert conventional dry land excavating equipment to an amphibious environment. Previous attempts to satisfy this demand have met with only limited success in part because the approaches taken were too complicated, and therefore too expensive. Some of the prior art attempts in this area utilized separate engines, one for the excavator itself, and one for the track drive, which of course increased weight, cost and maintenance requirements. Other proposals, such as those shown in U.S. Pat. Nos. 3,842,785 and 4,124,124 employed outboard lubricated chains extending between the prime mover and axles supporting the tracks on the pontoons. The drive chains presented serious environmental and safety hazards.
It is an object of this invention to provide a simple, inexpensive, uncomplicated adapter for rendering a dry land excavator amphibious.
A further object of the invention is to avoid the water pollution caused by open lubricated drive chains.
Yet another object is to enable an amphibious excavator to be driven by the standard excavator engine through its standard track motors; that is, to enable one to utilize the existing excavator engine and hydraulic motors to drive the tracks of an amphibious vehicle.
A further object is to avoid the hazards to personnel and animals posed by exposed drive chains.
The invention provides an adapter for converting a dry land earth mover to amphibious operation. The adapter comprises a pair of pontoon assemblies, each of these assemblies having a pontoon with an endless track guided around it in a generally vertical plane, a hydraulic drive motor powered by fluid from the prime mover of the excavator and a drive shaft assembly for transferring power directly from the hydraulic motor to the driven track. The drive shaft assembly includes a tube coaxial with the hydraulic motor and having an internal diameter greater than the outside diameter of the hydraulic motor to enable the tube to be placed over the hydraulic motor; a plate affixed to one end of the tube; a shaft affixed to the plate and coaxial with the tube for unitary rotation therewith; a pillow block for supporting the distal end of the shaft; and plural sprockets for supporting and driving the amphibious track, at least one of said sprockets being affixed to said tube and at least one of said sprockets being affixed to said shaft; whereby the track is driven directly from the hydraulic motor without intermediate linkage.